The invention relates to crankcase ventilation systems for internal combustion engines.
Crankcase ventilation systems for internal combustion engines are known in the prior art. An internal combustion engine generates blowby gas in a crankcase containing engine oil and oil aerosol. An air/oil separator has an inlet receiving blowby gas and oil aerosol from the crankcase, and an air outlet discharging clean blowby gas to the atmosphere or back to the engine air intake, and an oil outlet discharging scavenged separated oil back to the crankcase. The separator has a pressure drop thereacross such that the pressure at its inlet and in the crankcase is higher than the pressure at the separator air outlet and oil outlet. The pressure differential between the crankcase and the oil outlet of the separator normally tends to cause backflow of oil from the higher pressure crankcase to the lower pressure oil outlet. It is known in the prior art to locate the oil outlet of the separator at a given vertical elevation above the crankcase and to provide a vertical connection tube therebetween with a check valve to in turn provide a gravity head overcoming the noted pressure differential and backflow tendency, in order that oil can drain from the separator to the crankcase.
The present invention provides another solution to the above noted problem in a simple and effective manner.